Panel With Improved Coupling Means

ABSTRACT

The present invention relates to a new floor or wall panel with improved coupling means and is aimed at offering a solution for the drawbacks of the “fall down” joining system.

The present invention relates to, on the one hand, a panel (profiled strip) with improved connecting means (coupling means). The panel may be both a floor and a wall panel. On the other hand, the present invention relates to a method for forming such a panel (profiled strip).

Several systems are known to connect floorboards without using gluing methods, said systems differing in the way the floorboards can be joined. The main groups are as follows:

For the long side of the floorboard:

-   -   a) Connecting one floorboard horizontally and the other         floorboard via an angle to the first floorboard;     -   b) Connecting one floorboard horizontally and the other         floorboard via a rotating movement with the first floorboard.

Most of the currently known systems are described in the following patent publications: BE 9600527; BE 9700344; EP 0843763 and EP 1026341.

For the short side of the floorboard, once the longitudinal connection has been effected:

-   -   a) Joining both floorboards via a horizontal movement with         respect to one another, the so-called “snap connection”;     -   b) Connecting one floorboard horizontally and the other         floorboard via a vertical movement to the first floorboard.         These are so-called “fall-down or push-down” connections.

A significant drawback of the horizontal movement, more widely known as the snap-movement, of the floorboards with respect to one another is the fact that, on the one hand, an accessory and a hammer are required and that the hammering force, which is applied in order to join the floorboards together, may cause damage to the decorative top layer. The same may occur if the accessory is not handled correctly which serves to prevent damage to the protruding tongue on the other end of the floorboard to be connected. When using the hammer in order to move the floorboards horizontally with respect to one another, the force used to hammer the correctly placed accessory has to be regulated in order to achieve such a connection. In addition, it is also important to move the moving floorboard steadily towards the other floorboard, likewise in order to prevent damage. Practice shows that this is almost impossible, due to the point-concentrated load of the hammer.

Due to the above-described problems regarding the horizontal snap connection, a user-friendly technology is being developed which involves vertically connecting the panel to be attached to the horizontally positioned panel, more particularly, the fall-down or push-down technology. The new technology largely solves the problems associated with the use of accessories and joining floorboards by hammering in a regulated manner.

However, with most common known techniques there is a problem regarding possible damage to the two decorated sides due to the vertical grating movement with respect to one another during the fall-down process.

Another common problem is the fact that the connection can absorb only small upward forces caused by unevenness of the floor. Often, the force with which the floorboards are joined is also the force with which they can come apart (cf. EP 0085196 and EP 0562402). Due to the fact that the floorboards are pushed downwards by a simple push of the thumb, this relatively small force is the same as the one with which the floorboards can come apart. In order to solve the latter problem, several versions are known which use inserts made from a different material than the floorboard itself (cf. EP 1 650 375 and EP 1 415 056).

It is an object of the present invention to offer a solution for the abovementioned shortcomings of the “fall down” joining system.

The object of the invention is achieved by providing a profiled strip comprising a visible side, a first end side provided with first male and first female connecting means, and a second end side which is situated opposite the first end side and is provided with second male and second female connecting means, in which the connecting means are suitable to join the end sides of adjoining profiled strips with one another by engagement of the male and the female connecting means, in which the profiled strip furthermore comprises first vertical locking means which are provided to produce a vertical lock between adjoining profiled strips, and in which the first vertical locking means are made from the same material as the profiled strip and comprise a pliable projection which forms part of the first or second male connecting means. Such a first locking means provides a flexible lock, as it were. Due to the fact that the first locking means are made from the same material, such profiled strips have the significant advantage that they can be produced quickly and in a very simple manner. This is in contrast with the known profiled strips, where the locking means are configured as a so-called insert which is fitted to a semi-finished product which is mainly composed of wood or a derivative thereof, for example MDF, HDF or chipboard (see for example WO 2007/141605).

In the context of the present invention, the vertical lock is understood to mean a lock extending in a vertical direction substantially at right angles to the surface of the visible side.

In a preferred embodiment of the profiled strip according to the invention, the first vertical locking means furthermore comprise a recess which forms part of the first or second female connecting means, and the pliable projection is configured to carry out a bending movement during the joining of the adjoining profiled strips in the direction of the adjoining end side by moving in the recess in order then to at least partly bend back into its original position when the first or second male connecting means engage in the first or second female connecting means.

In a more preferred embodiment, the profiled strip according to the invention is made in a single part. The profiled strip according to the invention, and therefore also the pliable projection, are preferably made from plastic, more particularly from PVC, PP and PE. This offers the advantage that such profiled strips can be used in order to create a floor or wall covering which is impermeable to water.

In a preferred embodiment, the profiled strip comprises a decorative top layer. Said top layer is preferably fixedly attached to the visible side of the profiled strip.

According to a particular embodiment of the profiled strip according to the invention, the profiled strip furthermore comprises second vertical locking means which are configured to provide a second vertical lock between adjoining profiled strips.

The second vertical locking means are formed by providing the one end side with an oblique side or a recess, preferably a V-shaped recess, and providing the other side with a similar oblique side or a projection fitting in the recess, preferably a V-shaped projection. In this way, a (vertical) lock is formed between adjoining profiled strips which is rather inflexible. In the case of a V-shaped projection for the second lock, use can be made of the possible compressibility of the material.

The abovementioned oblique sides which, in certain embodiments in which the pliable projection is provided on the first male connecting means, make the second vertical lock possible, are illustrated in FIGS. 1 to 6, and adjoin the side of the profiled strip which is situated opposite the visible sides. The oblique sides are provided in such a manner that the oblique side of the one profile will slide over the oblique side of the adjoining profile when joining adjoining profiled strips. In other embodiments (see FIGS. 7 to 11) in which the pliable projection is provided on the second male connecting means, the second vertical locking means are formed by the V-shaped projection and the V-shaped recess interacting therewith.

Due to the presence of both first female connecting means (1′D) and second male (1B) connecting means (see, inter alia, FIG. 2) with the profiled strip according to the invention, there is also a horizontal lock (in accordance with a horizontal direction at right angles to the end sides) in addition to the vertical lock. The first female connecting means are configured as a cavity, while the male connecting means are configured as a projection which engages in said cavity.

Another subject of the present invention is a method for forming a profiled strip comprising: a first end side provided with first male and first female connecting means, a second end side situated opposite the first end side and provided with second male and second female connecting means, and first vertical locking means which are configured to produce a vertical lock between adjoining profiled strips, in which said locking means comprise a pliable projection, the method comprising the following steps:

-   -   forming a plate-shaped profile from plastic;     -   sawing the formed profile to the desired length;     -   performing a machining operation on the end sides of the sawn         profile in order to form the connecting means and the first         vertical locking means.

According to a preferred method, said profiled strip furthermore comprises second vertical locking means which are configured to produce a second vertical lock between adjoining profiled strips, in which said second vertical locking means are provided during said machining operation.

The method according to the invention is in particular designed to form a profiled strip as described in the attached claims. As a result thereof, the recess—in which the pliable projection fits when the two profiled strips are joined together—will also be formed during the machining operation.

It is evident that in a more preferred method, the required recesses, projections and/or bevelled edges are also provided via a machining operation in those cases where a double vertical lock is required.

It is evident that the longitudinal sides also have to be provided with connecting means in order to join profiled strips to one another along their longitudinal sides.

The present invention furthermore relates to a floor or wall covering made from a number of the above-described profiled strips.

In order to illustrate the characteristics of the present invention and to indicate additional advantages and features thereof, a more detailed description of the profiled strip (the floor panel) according to the invention will now be given. It will be clear that nothing in the following description can be interpreted as a restriction to the protection defined in the claims.

In this description, reference numerals are used to refer to the attached drawings, in which:

FIGS. 1 to 5: show the joint between two floorboards according to a first embodiment according to the invention;

FIG. 6: shows the joint between two floorboards according to an alternative (second) embodiment according to the invention;

FIGS. 7 to 9: show a number of alternative (third) embodiments;

FIGS. 10 and 11: show how the profiles illustrated in FIG. 8 are positioned with respect to one another, before and during fitting thereof.

The above elements 1 and 1′ to be joined together are floorboards substantially composed of polymer or polyolefines. The materials which can be used for the floorboards 1 and 1′ depend on the mechanical properties, more particularly the flexibility of the movable part 1′7. The floorboards have a decorative finish on the top side 11 and 1′1, and have a critical point 12 and 1′2 at the end of each decorative side which may cause damage when the floorboards are joined together. Both floorboards 1 and 1′ have connecting means 120 and 1′20, respectively, consisting of a notch 1A and 1′D, respectively, and a projecting part 1B and 1′C, respectively. The projecting part 1′C of the connecting means 1′20 of floorboard 1′ is in addition provided with a movable part 1′7 which forms an integral part of the connecting means 1′20 which in turn forms an integral part of the floorboard 1′.

The movable part 1′7 has a double function. On the one hand, it will ensure the ends of the decorative sides 12 and 1′2 cannot come into contact with one another until the very last moment during the joining process when the floorboard 1′ is being joined to floorboard 1 and the associated downward movement. In addition, the movable part 1′7 will provide a first lock of floorboard 1 with floorboard 1′ after it has engaged into the recess 111 which forms part of the notch 1A of the connecting means 120.

However, the present design also provides an additional lock as, depending on the base material of the floorboards to be joined, the dimensions of the movable part 1′7 have to be modifiable. For a hard, less flexible base material, the present design provides the possibility to give the movable part 1′7 a different design than for a soft, more flexible material, and this without any significant effect on the force K which is necessary to join the floorboards together and the force F which could separate the floorboards from one another or could move point 12 with respect to point 1′2 after fitting.

The additional lock of the floorboards 1 and 1′ is achieved in the following way. After floorboard 1′ has been moved vertically H with respect to floorboard 1 across distance E1, the oblique side 1′4 of the notch 1′D of the connecting means 1′20 comes into contact with the oblique side 14 of the projecting part 1B of the connecting means 120. During the vertical movement, the movable part 1′7 also still has its original shape and is not yet subjected to bending. During the vertical displacement H of floorboard 1′ with respect to floorboard 1 across distance E1, the movable part 1′7 acts as a spacer between the end of the decorative sides 12 and 1′2. During the displacement H across the distance E1, the end 1′3 of the movable part 1′7 comes into contact with the side 17 which forms part of floorboard 1.

The additional lock is achieved during the oblique displacement of floorboard 1 with respect to floorboard 1′ in the direction Z across the distance E2 along the oblique sides 14 and 1′4. This is due to the fact that the projecting part 1B of the connecting means 120 of the floorboard 1 is provided with an oblique side 15. The notch 1′D of the connecting means 1′20 is likewise provided with an oblique side 1′5. During the oblique displacement in the direction Z, the oblique side 1′5 will move along the oblique side 15. The projecting part 1′30 underneath the oblique side 1′5 of the floorboard 1′ is now below part 130 of floorboard 1 and will provide additional resistance to an upward force F caused by certain uneven structures on the floor FL.

During this displacement in the direction Z across the distance E2, the movable part 1′7 will also move X in the recess 1′6 of the projecting part 1′C in order to make a displacement in the oblique direction Z of floorboard 1′ with respect to floorboard 1 possible. As the movable part 1′7 moves in the recess 1′6, the ends of the decorative sides 12 and 1′2 will now finally start to move towards one another.

At the end of the displacement Z across the distance E2, the bottom side 1′10 of the projecting part 1′C will come into contact with the top side 110 of the notch 1A. Just before this happens, the movable part 1′7 will also move in the recess 111 which forms part of the notch 1A. The movable part 1′7 will assume its original position again and the recess 1′6 will also assume its original shape. Once this has happened, a lock has been achieved due to the contact of the top side 1′9 of the movable part 1′7 with the side 19 of floorboard 1.

In order to absorb the upward force F caused by uneven structures on the floor, 2 locks have been achieved, i.e. one as a result of the contact between the oblique wall 15 and 1′5 and one as a result of the contact between the oblique wall 1′9 of the movable part 1′7 and the oblique side 19 of floorboard 1. The double lock has been achieved.

It is not until the end of the entire joining process and the movement of floorboard 1′ with respect to floorboard 1 across the vertical distance E1 and the displacement E2 at an angle that the decorative ends 12 and 1′2 come into contact with one another and there is therefore no risk of damage to these decorative ends, as they do not have to slide across one another during the joining process and can adjoin one another without the use of force, once the joint has been achieved.

It should also be noted that a force K has been exerted in the vertical direction during the entire joining process and that the design of the connecting means 120 and 1′20, has automatically resulted in a movement in the vertical direction H and the movement at an angle Z.

Due to the double lock, the force F used to release the joint will have to be significantly higher than the force K which was required to achieve the joint, which are basic characteristics in the industry for a simple, high-quality joint between floorboards.

In addition, the additional lock at the location of the oblique side 15 and 1′5 makes it possible to join floorboards of different types which are made from various materials and have different mechanical properties to one another without requiring additional investment and without having to sacrifice the joining force, by means of a simple change in the dimensions of the movable part 1′7 by a simple displacement of a milling cutter.

A profiled strip (floorboard) comprising: a first end side provided with first male and first female connecting means, a second end side which is situated opposite the first end side and is provided with second male and second female connecting means, and first vertical locking means which are configured to provide a vertical lock between adjoining profiled strips, in which said locking means comprise a pliable projection, is formed by means of a method which at least comprises the following steps:

-   -   forming a plate-shaped profile from plastic;     -   sawing the formed profile to the desired length;     -   performing a machining operation on the end sides of the sawn         profile in order to form the connecting means and the first         vertical locking means.

It is evident that if said profiled strip furthermore comprises second vertical locking means which are configured to provide a second vertical lock between adjoining profiled strips, said second vertical locking means are provided during said machining operation.

A description is given below of a number of ways in which the plate-shaped profile can be formed.

The production process starts with transporting the various materials (in powder and in granular form), by means of a screw conveyor, to a premixer where a first cold mixing is carried out. The premixer will in turn transport the mixed material to a funnel which is provided with a metering screw at the bottom. This metering screw is also provided with a smaller funnel through which other additives can be added, such as blowing agents, colour pigments and, optionally, stabilizers or other additives which may be required to ensure an optimum formulation. The metering screw provides a continuous stream of base material to the heated cylinder which is provided with one or more heated screws in an extruder. The main parameter of the extruder is the L/D ratio or, more accurately, the ratio of the length of the cylinder to the diameter of the cylinder. This ratio is of great and defining importance in order to be able to process certain materials and to produce a PVC plate of the correct hardness.

The cylinder and screws of the extruder are given special treatment and are hardened against corrosion and mechanical wear. The cylinder and screws are composed of different zones, each of which can be controlled and adjusted individually in order thus to be able to heat or cool each zone separately. The quality of the product is greatly dependent on the production parameters which are used. Relevant production parameters are the melting point, cylinder temperature, die temperature, mass pressure and mass temperature. In addition to the L/D ratio, the screw geometry is essential, the correct distance between the flanges of the screw and the structure of the mixing zone on the screw is crucial for satisfactory plastification. The degassing zone in the cylinder of the extruder ensures that the gasses which have accumulated during the heating process are removed and the position thereof is also crucial to achieving a good result. While the screws transport the material to the die, the material has to be heated, homogenized and plastified/plasticized. Each material has a different plasticizing process and therefore the composition of the material is so important to the selected L/D ratio. At the end of the extruder, a die is provided which ensures that the material flowing out of the intruder will already have a certain flat shape and ensures that this process is carried out in optimum fashion. The thickness of the plate can be modified by adjusting the cooled lips at the front of the die to the correct thickness. The parallelism of the plate across the entire width is, on the one hand, controlled by a vertically displaceable control lath which is situated in the die and by adjustment of the calender, as the extruded material, upon leaving the die, will pass through a calender.

The calender is provided with three cylinders (the hollow cylinders are provided with water), each of which can be controlled individually in order to be able to set the correct temperature for each cylinder. The parameters which are essential in this process are the speed, temperature, opening between the cylinders, diameter of the cylinder, treatment of the surface of the cylinder.

Using this process, the plate is cooled down and calibrated. First, the plate is passed between 2 cylinders and thus follows the rotational speed of the central cylinder in order to thus be transferred to the 3rd cylinder which then transfers the plate to the roller track. By using the adjusted diameter of the cylinder or by using several cylinders, it is possible to cool down the plate sufficiently, so that the plate becomes sufficiently rigid in order to then be transported further on the roller track. If the plate has not cooled down sufficiently, it can be cooled still further in a water tank. The quality and treatment of the cylinder ensures that the plate acquires the desired surface quality. The following line is provided with a long roller track (if desired with water tank), draw bench and sawing machine. The length of the roller track and any associated water tank is defined in such a manner that the plates are completely cooled down when they reach the draw bench. The speed of the draw bench is adapted to the extrusion speed and the following speed of the saw. After sawing, the plates are placed on a pallet and, after a predetermined conditioning period, they are ready for processing.

With a possible variant on this production process, no die is used and the material passes straight from the extruder to a calender which consists of several, optionally heated rollers which form the plate to the desired thickness. If the desired thickness cannot be achieved via this process using one extruder, several extruders can be used and the plates produced by the various extruders will be laminated on top of one another using heat. In this way, the desired plate can also be achieved, although it will be composed of various layers. The advantage of this process is the largely higher production speed and the possibility of providing the different layers with different materials/properties. Thus, it is possible to provide a soft top layer on a hard base plate using more than one extruder in the production process.

A third possible variant consists of a combination of the abovementioned processes by using a die but also using more than one extruder. This is referred to as a coextrusion process and is similar to the 1^(st) abovementioned process, except that several extruders are used in order to be able to optionally change the material composition in the coextrusion layer or the base layer. In this process, it is also possible, if desired, to use an air or water cooling mechanism of the plate instead of a calender after the material has flowed out of the die in plate shape. The following steps in the production process are similar to those in the above descriptions, i.e. to the draw bench and saw bench via a roller track.

Once the plate has been produced in accordance with one of the described production processes, this plate may, if necessary, furthermore be provided with a decorative top layer.

If this decorative top layer can be joined to the extruded or calendered plate using heat, this top layer can be provided at the location of the calender if the temperature of the extruded or calendered plate is still sufficiently high or the plate can be heated after leaving the extrusion line in order to be able to attach the decorative top layer. This decorative top layer can also be applied by using an adhesive bonding technique instead of using heat.

During the last step in the production process, the produced plates are sawn into smaller formats and provided with the above-described connecting and locking means at the (head) ends of the sawn plates via a machining operation, for example by means of a milling device. The longitudinal sides are also provided with connecting means (coupling means) using the known techniques. 

1. Profiled strip (1) comprising a visible side (11), a first end side provided with first male (1′C) and first female connecting means (1′D), and a second end side which is situated opposite the first end side and is provided with second male (1B) and second female (1A) connecting means, in which the connecting means are suitable to join the end sides of adjoining profiled strips (1, 1′) with one another by engagement of the male and the female connecting means, in which the profiled strip furthermore comprises first vertical locking means which are provided to produce a vertical lock between adjoining profiled strips, wherein the first vertical locking means are made from the same material as the profiled strip (1) and comprise a pliable projection (1′7) which forms part of the first or second male connecting means.
 2. Profiled strip (1) according to claim 1, wherein the first vertical locking means furthermore comprise a recess which forms part of the first or second female connecting means, and in that the pliable projection is configured to carry out a bending movement during the joining of the adjoining profiled strips in the direction of the adjoining end side by moving in the recess (1′6) in order then to at least partly bend back into its original position when the first or second male connecting means engage in the first or second female connecting means.
 3. Profiled strip (1) according to claim 1, wherein the profiled strip is made in a single part.
 4. Profiled strip (1) according to claim 1, wherein the profiled strip is made from plastic.
 5. Profiled strip (1) according to claim 1, wherein the visible side comprises a decorative top layer.
 6. Profiled strip (1) according to claim 1, wherein the profiled strip (1) furthermore comprises second vertical locking means which are configured to provide a second vertical lock between adjoining profiled strips.
 7. Profiled strip (1) according to claim 6, wherein the second vertical locking means are formed by providing the one end side with an oblique side (15) or a recess (a) and providing the other side with a similar oblique side (1′5), respectively, or a projection fitting in the recess.
 8. Method for forming a profiled strip (1) comprising: a first end side provided with first male and first female connecting means, a second end side situated opposite the first end side and provided with second male and second female connecting means, and first vertical locking means which are configured to produce a vertical lock between adjoining profiled strips, in which said locking means comprise a pliable projection, wherein the method comprises the following steps: forming a plate-shaped profile from plastic; sawing the formed profile to the desired length; performing a machining operation on the end sides of the sawn profile in order to form the connecting means and the first vertical locking means.
 9. Method according to claim 8, wherein said profiled strip furthermore comprises second vertical locking means which are configured to produce a second vertical lock between adjoining profiled strips, in which said second vertical locking means are provided during said machining operation. 